REYES, J.B.L., J.:

This is  an  appeal from the  decision of the Court of Appeals affirming the judgment of the Court of First Instance of Ilocos Norte  finding petitioner Severino P. Justo guilty of the crime of  assault upon a person in authority. The Court of Appeals found the following facts to have been  established. 

"The offended party Nemesio B. de la Cuesta is a duly appointed district supervisor of the  Bureau of Public Schools, with station at Sarrat, Ilocos Norte.   Between 9:00 and 10:00 a.m. on October. 16, 1950, he went to the division office in Laoag, Ilocos Norte, in answer to a call from said office, in order to revise the plantilla of his district comprising ,the  towns of Sarrat and Piddig. At  about 11:25 a.m., De la Cuesta was leaving the office in order to take his meal when he saw the  appellant conversing with Severino  Caridad, academic supervisor.   Appellant requested  De  la Cuesta to go with him, and Caridad to the  office of the latter.  They  did and in  the office of Caridad, the appellant asked about the possibility  of accommodating Miss Racela as  a teacher in the  district of De la Cuesta.  Caridad said that there  was no vacancy, except that of the position of shop teacher.  Upon  hearing Caridad' answer, the appellant sharply addressed the complainant thus: "Shet, you are a double crosser.  One who cannot  keep his promise."  The appellant then grabbed a lead paper  weight from the table of Caridad and challenged the offended party  to go  out.  The appellant left Caridad's office, followed by De la Cuesta.  When they were in front of the table of one Carlos Bueno, a clerk in the division  office, De la Cuesta asked the appellant to put down the paper weight but instead the appellant grabbed the neck and collar of the polo shirt of the complainant which was torn.  Carlos Bueno separated the protagonists, but not before the complainant had boxed the appellant  several times."   (Petitioner's Brief, pp. 17-18).

The  present appeal is directed against that part of the decision of the Court of Appeals which says: 

"*  * * 'It is argued  by  Counsel, however, that  when  the  complainant accepted the challenge to a fight and followed the  appellant  out of the room  of Mr. Caridad, the offended party was no longer  performing his duty as a person in authority.  There is  no merit in this  contention.  The challenge  was the result of  the heated discussion between the complainant and the appellant occasioned by the latter's disappointment when he was told  that Miss Racela could  not be accommodated in the district of the former as  there was no more vacancy in  said district except that of a shop teacher. Be this as it  may, when the appellant grabbed the  neck and collar of the shirt  of the complainant, which is actually laying hands upon a person in authority, he did so while the latter was engaged in' the performance of his duties as the occasion of such  performance, to  wit:  his failure  to accommodate  Miss Racela as a teacher in his  district  as he had supposedly promised the appellant."   (Petitioner's Brief, pp. 22-23.)

Petitioner argues: 

(1)  that when the  complainant accepted his challenge to fight outside and followed him out  of the room of Mr.  Caridad where they had a verbal clash, he (complainant)  disrobed himself  of the mantle  of .authority and  waived the privilege of protection as a  person in authority; and 

(2).  that,the Court of Appeals erred in not holding that there was no unlawful aggression on petitioner's part because there was a  mutual agreement  to fight.

Neither argument is tenable.  The character of person in authority is not assumed or laid off  at will, but attaches to a public official until he ceases to be in office.  Assuming that the complainant was not actually performing the duties of his office when assaulted,  this fact does not  bar  the existence of the crime of assault upon a person in authority; so long as the impelling motive of the attack is the performance of official duty.   This is  apparent from the phraseology of Article 148 of our Revised  Penal Code, in penalizing attacks upon person  in authority "while engaged in the performance of official duties  or on  occasion of such performance", the words "on occasion" signifying" "because" or "by reason" of the past performance of official duty, even if at the very time  of the assault no official duty was being discharged (People vs. Garcia, 20 Phil.,  358; Sent, of the Tribunal Supremo of Spain, 24 November 1874; 26 December 1877; 13 June 1882 and 31 December 1896).

Thus, the  Supreme Court of Spain  has ruled that: 

"No  es razon apreciable para  dejar de  constituir  el delito  de atentado el que no estuviera el guarda en el termino en que ejercia sus funciones, pues resultado que  se  ejecuto con ocasion de ellas, esta circunstancias siempre es suficiente, por si sola, para constituir el atentado, sin tener en cuenta el sitio en que haya ocurrido."   (Sent. 13 de  Junio de 1882) (1 Hidalgo, Codigo Penal,  642-643).

No  other  construction is compatible  with the evident purpose of  the law that public officials and their agents should be able to  discharge their  official duties without being haunted by the fear of being assaulted or injured by reason thereof.

The argument that the offended party, De la Cuesta, can not claim to have been unlawfully attacked because he had accepted  the accused's  challenge to fight,  overlooks the circumstance that  as found by the Court of Appeals, the challenge was to "go out", i.e., to fight outside the building, it not being logical  that the  fight  should  be held  inside the office building in the plain view of subordinate employees.  Even applying the rules in  duelling cases, it is manifest that an aggression ahead of the stipulated time and place for the encounter  would be unlawful; to hold otherwise would be to sanction unexpected assaults contrary to all  sense of loyalty and fair play.   In the present case, assuming that De la Cuesta accepted the challenge of the accused, the facts clearly indicate that he was merely on' his way out to fight the accused when the latter violently lay hands upon him.  The acceptance of the challenge did not place on  the offended party the burden  of preparing to meet an  assault  at any time  even before  reaching the appointed place for the agreed encounter,  and any such aggression was patently illegal.  Appellant's position would be plausible if the  complaining official had been  the one who issued the challenge to fight; but  here the reverse precisely  happened.

We find no reversible error in the decision appealed from, and  the same is hereby affirmed.  Costs against appellant.'

Paras,  C. J., Bengzon, Padilla, Reyes A., Bautista Angelo, Concepcion, and Endencia, JJ. concur.